JP2002248308A - Filter medium for chemical filter and chemical filter unit - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a filter medium for a chemical filter and a chemical filter unit, which are used in a clean room or the like for removing an acid or alkaline gas particularly and do not affect an article or the like adversely in the clean room and from which a gaseous contaminant is not generated or, if any, the amount of the contaminant to be generated is made extremely small. SOLUTION: This chemical filter unit is constituted by using the filter medium obtained by laminating a physical adsorption layer for adsorbing contaminants to be generated from an ion exchange resin layer on the downstream side of the ion exchange resin layer. A cover material from which the amount of the gaseous contaminant to be generated is made small can be arranged on the downstream side of the physical adsorption layer.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

[Prior art]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a semiconductor or liquid crystal production facility, or a clean room used in connection with semiconductor or liquid crystal peripheral technology, which is included in the air or atmosphere in the production facility or the clean room. The present invention relates to a chemical filter material and a chemical filter unit for removing organic and inorganic gaseous pollutants to be removed.

[0002]

2. Description of the Related Art In a semiconductor or liquid crystal production facility, or in a clean room or the like used in connection with semiconductor or liquid crystal peripheral technology, high cleanliness is required for air and atmosphere in the production facility or the clean room. However, such air and atmosphere contain organic gaseous pollutants and inorganic gaseous pollutants. Since pollutants are generated, a filter material for a chemical filter and a chemical filter unit are used to remove such gaseous pollutants.

[0003] Of the gaseous pollutants, acidic gases such as sulfur dioxide are said to cause corrosion due to the presence of moisture in the air when they come into direct contact with metal parts such as aluminum wiring layers. In addition, when a basic gas such as ammonia is present, protons generated by the chemically amplified resist are consumed, which may cause a reduction in pattern resolution, or may cause adsorption or reaction on glass or mirror surfaces to generate precipitates. Is said to cause trouble.

[0004] Further, among the gaseous contaminants, organic substances having low polarity can be removed by surface cleaning or heating if they are in a small amount even if they are physically adsorbed on the surface of a silicon wafer or a glass substrate. Removal becomes difficult. And especially highly polar organic substances such as additives among the pollutants,
After becoming gaseous, it is firmly adsorbed on the surface of a silicon wafer or a glass substrate and cannot be easily removed. For example,
It is considered that dioctyl phthalate as a plasticizer used for a polymer material has a strong adhesive force on a wafer, and displaces a substance having a weak adhesive force already adhered on a wafer.

[0005] Such additives are substances added to improve the functionality of polymer materials and the like, such as plasticizers, antioxidants, ultraviolet absorbers, light stabilizers, flame retardants, lubricants, There are an antistatic agent, a nucleating agent, a foaming agent and the like. And as the material of these additives, in particular, phthalate ester plasticizer, trimellitate ester plasticizer, aliphatic dibasic ester plasticizer, fatty ester plasticizer, epoxy plasticizer, phosphoric acid Ester-based plasticizer, polyester-based plasticizer, phenol-based antioxidant, thio-based antioxidant,
There have been problems with phosphorus-based antioxidants, benzotriazole-based ultraviolet absorbers, benzophenone-based ultraviolet absorbers, UVA ultraviolet absorbers, hindered amine-based light stabilizers, phosphorus-based flame retardants, and the like.

[0006] In order to prevent these organic substances from adsorbing on the wafer surface, the concentration of the organic substances in the clean room atmosphere must be controlled at a level as low as possible. 19
1999 edition of SIA (Semiconductor Ind.)
According to the U.S. Association Roadmap, the level of organic substance management on the wafer surface in the year 2000 is 6.6 × 10 ¹³ Cats / cm ² . When this is converted into toluene, it is 1.44 ng / c.
m ² . In general, dioctyl phthalate having a strong adhesive force on a wafer is 0.2 ng on the wafer.
It is said that the deposition of / cm ² causes dielectric breakdown of the gate oxide film, and this value is considered to be the control level on the wafer surface. When the estimated value of the control level in clean room air is calculated from the value of the control level on the wafer surface and the generally known adhesion probability by the following formula, the control concentration of the total organic substance is 41.7 μg. /
The control concentration of a substance having a strong adhesive force such as m ³ and dioctyl phthalate is 0.007 μg / m ³ . Calculation formula: N = As / (v · t · γ) N: Contaminant concentration in air (control concentration in air) (μg
/ M ³ ) As; Contaminant concentration on wafer surface (control level on wafer surface) (μg / m ² ) v; Clean room air flow rate (0.4 m / sec) t; Wafer exposure time in air (86400 sec) ) Γ: Attachment probability Attachment probability of aromatic hydrocarbons 1 × 10 ^-5 , Attachment probability of dioctyl phthalate ester etc. 1/120 to 1/160

Activated carbon, activated carbon fiber, zeolite, ion-exchange resin, ion-exchange fiber and other chemical adsorbents are used as adsorbents in the filter medium for chemical filters that adsorb such contaminants. In this publication, these adsorbents are held and used between two or more layers of air-permeable filter media.

[0008] Among the above adsorbents, ion exchange resins and ion exchange fibers, in particular, have extremely excellent adsorption capacities for acidic or basic gases. However, when the above contaminants in the gas to be treated are removed by a filter material for a chemical filter using the ion exchange resin and the ion exchange fiber, the above-mentioned organic contaminants are generated from the ion exchange resin and the ion exchange fiber itself. There was a problem of doing it. In spite of its excellent adsorption capacity, such filter materials for chemical filters are used for semiconductor and liquid crystal production facilities, or clean rooms used in connection with semiconductor and liquid crystal peripheral technologies. There was a problem that you can not.

[0009]

DISCLOSURE OF THE INVENTION The present invention relates to a filter material and a chemical filter unit for a chemical filter which can be used in a clean room or the like and which can remove acidic or basic gas in particular. An object of the present invention is to provide a filter material and a chemical filter unit for a chemical filter that do not generate gaseous pollutants or generate very little gaseous pollutants and do not adversely affect products in a clean room. .

[0010]

According to a first aspect of the present invention, a physical adsorption layer for adsorbing contaminants generated from the ion exchange resin is provided downstream of the ion exchange resin layer. A filter material for a chemical filter characterized by being laminated, wherein a gas to be treated is a contaminant generated from the ion exchange resin layer by providing a physical adsorption layer at a position downstream of the ion exchange resin layer for the gas to be treated. Can be removed by the physical adsorption layer, so that acidic or basic gas can be removed without releasing pollutants into the gas to be treated.

[0011] In the invention of claim 2, the ion exchange resin layers, the physical adsorption layers, or the ion exchange resin layer and the physical adsorption layer are joined and integrated by a heat-fusible resin. The filter material for a chemical filter according to claim 1, wherein such a structure facilitates pleating and, when installed on a frame of the filter, facilitates unitization.

[0012] According to a third aspect of the present invention, there is provided the filter material for a chemical filter according to the first or second aspect, wherein the physical adsorption layer contains an acidic gas adsorbent and / or an alkali gas adsorbent. By using an adsorbent that has the ability to adsorb acidic or basic gases in the physical adsorption layer, contaminants generated from ion-exchange resins or ion-exchange fibers can be removed, further improving the ability to adsorb acidic gases or basic gases. Can be done.

[0013] Further, according to the invention of claim 4, one surface of a web composed of a plurality of lamination units, and the lamination unit is composed of a connecting portion made of a hot melt resin and a resin aggregation portion,
An ion exchange resin particle or a physically adsorbed particle is fixed through the resin aggregation portion, and the other surface of the web,
The ion exchange resin particles or the physically adsorbed particles constituting another laminated unit are fixed to each other via a resin aggregation portion, and the laminated unit is the ion exchange resin layer or the physically adsorbed layer. The filter material for a chemical filter according to any one of claims 1 to 3, wherein a pleat is easily formed by such a structure, pressure loss does not increase, and the filter material is installed in a filter frame. Unitization is easy.

[0014] In the invention of claim 5, the cover material is provided further downstream of the layer laminated at the most downstream position.
In the chemical filter unit composed of the filter material for a chemical filter described in the above item, the total amount of organic substances (weight in terms of toluene) generated from the cover material is calculated by estimating the generated gas by 2.
Calculated at 3 ° C., the total amount of organic substances is 1.0 (pg / m ² · hr) or more per 10 cm (μg / m ² · hr) per frontage area of the chemical filter unit and per unit time.
hr) a chemical filter unit which is less than or equal to or less than, and uses a gas-permeable cover material for preventing scattering of the physical adsorbent when using a physical adsorbent which may be scattered. By providing it on the further downstream side, the influence on the products in the clean room due to the scattering of the physical adsorbent can be reduced.

[0015] In the invention of claim 6, the cover material is provided further downstream of the layer laminated at the most downstream position.
In the chemical filter unit comprising the filter material for a chemical filter described in the above item, the amount of the additive (weight in terms of toluene) generated from the cover material is determined by estimating the generated gas at 23 ° C.
Calculated in the above, the amount of the additive per unit area of the front of the chemical filter unit and per unit time.
0 (pg / m ² · hr) or more and 0.15 (μg / m ² · h)
r) The following chemical filter unit, wherein when using a physical adsorbent which may be scattered, a gas-permeable cover material for preventing the physical adsorbent from being scattered is physically adsorbed to the gas to be treated. By providing it on the further downstream side, the influence on the products in the clean room due to the scattering of the physical adsorbent can be reduced.

[0016]

BEST MODE FOR CARRYING OUT THE INVENTION Hereinafter, preferred embodiments of a chemical filter material and a chemical filter unit according to the present invention will be described in detail.

The ion-exchange resin layer of the present invention may be a layer of a gas-permeable sheet made of ion-exchange fibers, or a sheet-like form obtained by accumulating particulate ion-exchange resin, or a particulate ion-exchange resin. This is a layer in which the resins are bonded to each other with a heat-fusible resin to form a sheet, or a layer obtained by supporting a particulate ion exchange resin or a fibrous ion exchange resin on a support. Examples of the air-permeable sheet made of ion-exchange fibers include non-woven fabrics, woven fabrics, and porous materials such as filter paper. Among them, non-woven fabrics are preferable because of high air permeability. Further, as the support supporting the ion exchange resin, any sheet-like material having air permeability can be used. As such a sheet-like material, non-woven fabric, woven fabric,
Examples thereof include a porous body such as a membrane, filter paper, and sponge. Among them, a nonwoven fabric is preferable because of high air permeability. In addition, if the sheet-like material as the support is a polymer material, it has high followability to pleated folding in filter processing,
Since it is excellent in durability, it can be preferably used.
In addition, it is desirable to use a resin that generates a small amount of gas as a heat-fusible resin for joining the ion exchange resin.

[0018] The physical adsorption layer of the present invention may be a layer of a breathable sheet made of fibers having physical adsorption capacity, or a sheet formed by accumulating particulate physical adsorbents, or a sheet. This is a layer in which the physical adsorbent is bonded to each other with a heat-fusible resin to form a sheet, or a layer obtained by supporting the physical adsorbent on a support. As fibers having physical adsorption capacity,
Activated carbon fibers or fibers obtained by adding an ability to adsorb an acidic gas or a basic gas to activated carbon fibers can be used. A porous material having a specific surface area of 200 m ² / g or more can be selected and used. And more preferably 500 m ² / g or more. Examples of the sheet-like material having air permeability include porous materials such as nonwoven fabric, woven fabric, and filter paper. Among them, nonwoven fabric is preferable because of high air permeability. Further, as the support supporting the physical adsorbent, any air-permeable sheet material can be used, and such air-permeable sheet materials include nonwoven fabrics, woven fabrics, and the like.
Examples thereof include a porous body such as a membrane, filter paper, and sponge. Among them, a nonwoven fabric is preferable because of high air permeability. Further, if the sheet-like material used for the support is a polymer material, it has a high followability to pleated folding in filter processing,
Since it is excellent in durability, it can be preferably used.
Next, as the physical adsorbent, any one can be used as long as it can be used for deodorizing purposes, and activated carbon, activated carbon fiber, zeolite, and the like can be preferably used. A physical adsorbent to which the ability to adsorb the water is added may be used. The physical adsorbent is preferably selected from porous materials having a specific surface area of 200 m ² / g or more, and more preferably 500 m ² / g or more. Further, it is desirable to use a resin that generates a small amount of gas as a heat-fusible resin for joining the physical adsorbent. The physical adsorption layer thus obtained can adsorb contaminants generated from the ion exchange resin downstream of the ion exchange resin layer.

In the filter material for a chemical filter of the present invention,
In addition to the ion exchange resin layer and the physical adsorption layer, a layer that does not generate gaseous pollutants or a layer that generates less gaseous pollutants may be laminated. In such a layer, the particles of the inorganic adsorbent and the inorganic catalyst are accumulated to form a sheet, or the particle-shaped inorganic adsorbent and the inorganic catalyst are bonded to each other with a heat-fusible resin to form a sheet. Layer, a layer obtained by supporting an inorganic adsorbent or an inorganic catalyst on a support, or a dust removing layer. Any of the above-mentioned supports can be used as long as it is a sheet having air permeability. Examples of such a sheet having air permeability include non-woven fabrics, woven fabrics, membranes, filter papers, porous materials such as sponges, and the like. Can be Examples of the dust removing layer include porous materials such as nonwoven fabric, woven fabric, membrane, filter paper, and sponge.

[0020] In the filter material for a chemical filter of the present invention, the lamination method may be any number of ion exchange resin layers and no physical adsorption layers, and the order of lamination may be arbitrary. In addition, it is necessary that at least one physical adsorption layer that adsorbs contaminants generated from the ion exchange resin is laminated. By providing the physical adsorption layer at a position downstream of the ion exchange resin layer for the gas to be treated, contaminants generated from the ion exchange resin layer can be removed by the physical adsorption layer. The removal of the acidic or basic gas from the gas to be treated can be realized without releasing the gas. When the layer laminated at the most downstream position is a layer containing an adsorbent or the like, a form in which the adsorbent or the like is less likely to scatter than the layer is preferable. It is not always necessary to join the laminated layers, but it is preferable that the layers are joined and integrated because the pleating process is easy and the unit is installed on the frame of the filter to be processed into a unit called a unit.

For joining and integrating the laminated layers, a thermoplastic polyamide resin, a thermoplastic polyester resin,
A heat-fusible resin such as a thermoplastic urethane resin, a polyolefin resin, and an ethylene-vinyl acetate copolymer resin can be used in the form of particles or a nonwoven fabric. The bonding method is, for example, in the case of a gas-permeable sheet-like layer made of ion-exchange fibers and a gas-permeable sheet-like layer made of fibers having physical adsorption ability, a heat-fusible resin is used between the layers. , And the entire laminate can be heated and joined. Further, in the case of a layer obtained by supporting a particulate ion exchange resin on a support and a layer obtained by supporting a physical adsorbent on a support, a nonwoven fabric made of a heat-fusible resin is laminated between the layers. Thus, the entire laminate can be heated and joined. Further, for example, a spunbonded nonwoven fabric such as polyester is used as a support, and a particle layer in which particulate ion-exchange resin particles and heat-fusible resin particles are mixed is formed thereon. After forming a particle layer in which the activated carbon particles and the heat-fusible resin particles are mixed, and heating the entire layer under pressure, the respective layers can be joined. In this case, the ion exchange resin particles or the activated carbon particles can be bonded in each layer simultaneously with the bonding between the layers.

In the case where the ion-exchange resin layer is a layer in which ion-exchange resin particles are accumulated to form a sheet, and the physical adsorption layer is a layer in which particles of the physical adsorbent are accumulated to form a sheet. As a method of joining and integrating, for example, as illustrated in FIG. 3, a web composed of a plurality of lamination units 8, the lamination units being composed of a connecting portion 5 made of a hot melt resin and a resin aggregation portion 6. An ion-exchange resin particle 7 or a physically adsorbed particle 7 is fixed to one surface via the resin aggregation portion 6, and the other surface of the web and an ion-exchange resin constituting another laminated unit are formed. There is a method in which the resin particles or the physically adsorbed particles are fixed via the resin aggregation portion, and the lamination unit is configured to be an ion exchange resin layer or a physically adsorbed layer and integrated. In this way, the obtained filter for a chemical filter is obtained. The material is easy to pleate and the pressure loss does not increase. In addition, when the unit is installed on the frame of the filter, unit processing is easy.
This is a preferred form as a filter material for a chemical filter.

[0023] The chemical filter unit of the present invention is obtained by installing the above-mentioned filter material for a chemical filter in a frame of the filter to make a unit. Examples of the unit form include a pleat-folded cross-flow and parallel-flow type illustrated in FIG. 1, a flat panel type illustrated in FIG. 2, and a honeycomb type. Also,
Materials such as metal and synthetic resin are used for the frame, and it is preferable to use any material that generates less gaseous pollutants.

When it is necessary to prevent scattering of a physical adsorbent or the like from the physical adsorption layer located at the most downstream position with respect to the passing direction of the gas to be treated, a cover having air permeability is provided downstream of the physical adsorption layer. It is preferred to further arrange the material. As the cover material, a nonwoven fabric or a membrane of a polymer material as an organic material, paper or pulp of a natural material, a mesh of aluminum or stainless steel as an inorganic material, etc. can be used. High loss and heavy weight may pose a problem, whereas polymer materials are preferred because such problems are small, and nonwoven fabrics having good air permeability are particularly suitable. However, for the cover material, it is necessary to use a material that does not easily generate gaseous organic substances and the like that contaminate the gas to be treated and adversely affect products in the clean room. The cover member can be disposed in close contact with the physical adsorption layer, or can be disposed at an air outlet portion from the chemical filter unit. In order to further enhance the scattering prevention effect, as shown in FIG. 4, a composite of a thermoplastic resin 5a and a physical adsorbing layer 8c can be used to adhere the cover material 3 to the cover material 3 as exemplified in FIG. . Further, as illustrated in FIG. 4, the ion exchange resin layer, the physical adsorption layer, and the cover material can all be integrated. In this case, pleating is easy, and the unit is installed on the frame of the filter. It is also preferable because it can be easily processed.

When a polymer material is used for the cover material, the polymer material is produced by polymerization of a monomer, and unreacted monomers remaining in the production process cause gaseous pollutants. In addition, oxidation, mechanical stress, chemicals,
In order to prevent deterioration due to water or the like and to make the polymer material resistant, the additive added to the polymer material becomes a generated gas and causes gaseous pollutants. Thus, generation of a small amount of organic substances is inevitable. Further, the polymer material used for the cover material is required to have properties such as fiberization and flexibility, compared to the polymer material used for the frame body, and thus an organic substance is more easily generated.

However, if the concentration of the generated organic substance is sufficiently lower than the control level, the problem that occurs in the clean room can be avoided. In the filter material for a chemical filter of the present invention, the physical adsorption layer immediately upstream of the cover material adsorbs organic substances generated in the ion-exchange resin layer further upstream thereof, so that only the gas generated from the cover material is considered. The amount of total organic substances and additives generated from the cover material at the standard condition temperature of 23 ° C.
The value calculated by the dynamic headspace method and the generated gas estimation method (described later in detail) is 1.0 (pg in total organic substance amount per frontage area of the chemical filter unit).
/ M ² · hr) or more 10μg / m ² · hr or less, in the additive ^{1.0 (pg / m 2 · hr} ) or more 0.15μg
If it is less than / m ² · hr, the problem occurring in the clean room can be avoided. The chemical filter unit of the present invention selects and uses a cover material meeting this condition.

For example, when a chemical filter unit as illustrated in FIG. 1 is prepared by pleating a filter material for a chemical filter provided with a cover member 3 on the downstream side as illustrated in FIG. Height of 3.3
cm, mountain 5mm, unit frontage 50cm × 50cm
Then, the area of the filter medium for a chemical filter used in this chemical filter unit is 3.3 cm × 2 × (50
cm / 5 mm) the area of × 50 cm = 3.3 m ² formula from about 3.3 m ^2. Here, for example, gas generated from the cover material of the filter medium for the chemical filter is, 1.233μg / m ² · hr in a total organic mass, in the additive amount When 0.0364μg / m ² · hr, the chemical filter The total amount of organic substances generated from the cover material of the unit was 4.07 μg / m ² · hr per frontage area of the chemical filter unit, and 0.1 in the amount of additive.
It is 2 μg / m ² · hr. The amount of gas generated from this cover material was 1.0 (pg / m ² · h) in total organic substance amount per frontage area of the chemical filter unit described above.
r) to 10 μg / m ² · hr and, for additives, 1.0 (pg / m ² · hr) to 0.15 μg / m ² · h
Since it falls within the range of r or less, this chemical filter unit is compatible with the chemical filter units according to claims 5 and 6 of the present invention.

Next, the effects when the chemical filter unit according to claims 4 and 5 of the present invention is used in a clean room will be described. For example, a chemical filter unit is installed, and the wind speed passing through the unit frontage at that time is 0.3 m
/ Sec, the total amount of organic substances generated from the cover material of the chemical filter unit is 10 μg / m
^{If 2} · hr, the concentration of pollutants in the air is 10 μg
/ M ² · hr ÷ 0.3 m / sec = 9 × 10 ^-3 μg / m ³
Thus, the above-mentioned management reference value of 41.7 μg / m ³ can be sufficiently satisfied. Similarly, the mass of the generated additive is 0.1.
In the case of 15 μg / m ² · hr, the contaminant concentration in the air is 0.15 μg / m ² · hr ÷ 0.3 m / sec =
1.4 × 10 ^-4 μg / m ³ next, 7 × 10 the control reference value mentioned above ^- can be sufficiently satisfied ^{3 μg} / m ^3. Also, if 90-95% of upstream gaseous pollutants are removed by the chemical filter unit, the remaining 10-5% of gaseous pollutants may enter the clean room by being combined with the gas generated from the cover material. become. The total gaseous pollutant concentration must be less than the control standard value, and considering the high concentration of gaseous pollutants in the upstream, especially outside air, the gas generated from the cover material should be as close to 0 as possible. Is desirable. However, according to the present invention, the concentration of contaminants due to total organic substances is 9 × 10 ⁻³ μg / g as described above.
Since the density is a very small value of m ³ , this requirement can be satisfied. Furthermore, most of the air that has entered the clean room returns to the chemical filter unit again as return air, so that the gas generated from the cover material of the chemical filter unit is removed by the chemical filter unit itself. But,
If the amount of gaseous pollutants is too large, the life of the chemical filter unit will be shortened. Therefore, it is necessary to generate as little gas as possible from the cover material of the chemical filter unit. However, according to the present invention, the contaminant concentration due to the total organic substance is 9 × 10
^Since the concentration has a very small value of ^-3 μg / m ³ , even if this air returns to the chemical filter unit as return air, the problem of shortening the life of the chemical filter unit does not occur.

The dynamic headspace method is a method using a principle that the generated gas is not proportional to the mass of the test piece but is proportional to the surface area. FIG. 5 shows a generated gas collecting apparatus (GL Science) used in this method. MSTD-258 manufactured by
It is explanatory drawing of M). First, the material to be measured is diameter 7c.
Cut into a circular shape of m to prepare a sample 1. The sample 1 is placed on the central gas outlet 13 in the chamber 10.
Next, clean helium gas 11 was introduced into the chamber at a flow rate of 1.
Heat at a predetermined temperature (60 ° C. or 80 ° C.) while continuously flowing at 20 ml / min. Helium gas 11
Since the contaminants generated from the sample 1 are mixed into the helium gas when coming into contact with the sample 1, after the gas concentration becomes equilibrium, the solid adsorbent 12 is collected at a collection rate of 100 ml / min.
(Component: 2,6-diphenylene oxide). Next, the substance collected by the solid adsorbent 12 is analyzed by a gas chromatograph mass spectrometer. (QP- manufactured by Shimadzu Corporation)
The heating temperature is measured under two conditions of 60 ° C. and 80 ° C.

Next, the generated gas estimation method is a method of conducting an accelerated test of the generated gas at a high temperature and estimating the result at room temperature by using an empirical formula. Will be described. Since the amount of gas generated at a room temperature of 23 ° C. in an actual clean room is extremely small, it is practically difficult to perform measurement, for example, a long time measurement is required in terms of analysis sensitivity. The conditions are set at a high temperature of, for example, 60 ° C. and 80 ° C., and the results at room temperature 23 ° C. are estimated from the results of qualitatively and quantitatively measuring the amount of organic substances generated from the sample using the following equation.
According to Takeda et al. Of Sumika Chemical Analysis Service Co., Ltd., it is known that the following equation holds as a rule of thumb for the relationship between test temperature and generated gas. (Described in the proceedings of the 17th Contamination Control Research Conference 1999) ln (M / A · h) =-C1 / T + C2 M; amount of gas generated in toluene (μg) A; measurement sample area ( m ² ) h; time required for collection (h) T; test temperature (absolute temperature K) C1 and C2;

Hereinafter, embodiments of the present invention will be described, but these are merely preferred examples for easy understanding of the present invention, and the present invention is not limited to the contents of these embodiments.

(Example 1) As illustrated in FIG. 4, as a support, a polyester spunbonded nonwoven fabric 2 (area density 3
0 g / m ² ) and a thermoplastic polyamide resin (melt index at 190 ° C .: 8)
A hot-melt nonwoven fabric 5 having a surface density of 20 g / m ^{2 made} of No. 0) was laminated as an adhesive layer. Next, commercially available strongly acidic cation exchange resin particles 7a classified to a particle size of 0.3 mm to 1.2 mm were sprayed on the adhesive layer so as to have an amount of 350 g per 1 m ² . Subsequently, a steam treatment of about 5 kg / cm ² is performed from the support side for about 7 seconds to plasticize and melt the adhesive layer, and thereafter, the strongly acidic cation-exchange resin particles that are not fixed are removed. Resin aggregation section 6
Then, the strongly acidic cation exchange resin particles 7a were fixed to obtain a first layered unit 8a. Further, the laminated unit 8a in this state
Is laminated with the same thermoplastic polyamide nonwoven fabric 5,
The second-layer laminated unit 8b was formed through the application of the strongly acidic cation exchange resin particles 7b, the steam treatment, and the removal of the strongly adhered strongly acidic cation exchange particles. Finally, the same polyamide resin nonwoven fabric 5 as described above is laminated, and the particle size is 0.3 to
The activated carbon particles 8c having a thickness of 0.5 mm were sprayed thereon and subjected to steam treatment and removal of unfixed activated carbon particles to obtain a third-layer laminated unit 8c. By the above procedure, a filter medium for a chemical filter was obtained in which the physical adsorption layer (activated carbon layer) 8c was laminated on the downstream side of the ion exchange resin layer 8b in the passing direction 4 of the gas to be treated.

(Example 2) A filter material for a chemical filter was obtained in the same manner as in Example 1, except that activated carbon impregnated with 10% by weight of phosphoric acid per 1 g of activated carbon was used instead of the activated carbon in Example 1. .

(Embodiment 3) As illustrated in FIG.
A hot-melt nonwoven fabric 5a having a surface density of 20 g / m ^{2 made} of a thermoplastic polyethylene resin (melt index at 190 ° C .: 200) is further laminated as an adhesive layer on the activated carbon side of the filter material for a chemical filter obtained in the above, and a cover thereon. After laminating a polyester spunbonded nonwoven fabric 3 having a surface density of 30 g / m ² as a material, a steam treatment of about 5 kg / cm ² was performed from the support side for about 7 seconds. By the above procedure, the physical adsorption layer (activated carbon layer) 8c is provided on the downstream side of the ion exchange resin layer 8b with respect to the passage direction 4 of the gas to be treated,
A filter material for a chemical filter having a polyester spunbond nonwoven fabric 3 as a cover material was obtained downstream of the physical adsorption layer 8c via a hot melt resin.

(Comparative Example 1) Two ion exchange resin layers were laminated in the same manner as in Example 1 except that the physical adsorption layer (activated carbon layer) 8c, which was the third laminated unit, was not laminated. The formed filter material for a chemical filter was obtained.

(Comparative Example 2) As shown in FIG.
A hot-melt nonwoven fabric 5a having a surface density of 20 g / m ^{2 made} of a thermoplastic polyamide resin (melt index at 190 ° C .: 80) is further laminated as an adhesive layer on the activated carbon side of the filter medium for a chemical filter obtained in the above, and a cover thereon. After laminating a polypropylene spunbonded nonwoven fabric 3 having a surface density of 30 g / m ² as a material, a steam treatment of about 5 kg / cm ² was performed from the support side for about 7 seconds. According to the above procedure, a physical adsorption layer (activated carbon layer) 8c is provided on the downstream side of the ion exchange resin layer 8b in the passage direction 4 of the gas to be treated, and the polypropylene is provided on the downstream side of the physical adsorption layer 8c via a hot melt resin. A filter material for a chemical filter to which the spunbonded nonwoven fabric 3 was fixed as a cover material was obtained.

(Evaluation Method of Gas Generation Amount from Cover Material) A method of evaluating the gas generation amount from the cover material will be described with reference to FIG. The cover material used in Example 3 or Comparative Example 2 using the cover material was 7c in diameter.
The sample 9 was cut into a circle, and two samples 9 each were prepared.
One of the samples 9 is placed on the central gas outlet 13 in the chamber 10 and then a clean helium gas 11
Was continuously heated at a flow rate of 120 ml / min in the chamber 10 to heat the chamber 10 to 60 ° C.
After 30 minutes, the solid adsorbent 1 was collected at a collection rate of 100 ml / min.
3 (component; 2,6-diphenylene oxide) was collected for 1 hour. For the other sample 9, the generated gas was collected by the same procedure with the heating rate of the chamber 10 set to 80 ° C. The generated gas at 23 ° C. is estimated by the above-described generated gas estimation method, and the cover per unit opening area of the unit when the filter material for a chemical filter is formed into a pleated type unit (3.3 cm in height, 5 mm in mountain). The results are shown in Table 1 in terms of the amount of gas generated from the material.

(Method of Evaluating the Amount of Gas Generated from Filter Material for Chemical Filter) A method of evaluating the amount of gas generated from the filter material for chemical filter will be described with reference to FIG. 5 which is an explanatory diagram of a generated gas collecting device. First, the filter medium for a chemical filter of each Example and Comparative Example was sandwiched between two cylindrical glass cells (not shown) having an inner diameter of 2.5 cm and capable of covering the peripheral edge thereof, and the periphery thereof was taped with PTFE (Teflon). (Registered trademark) tape so that the helium gas 11, which is the gas to be treated, does not flow again after passing through the sample 9 and come into contact with the adsorbent. Next, the cell into which the sample 9 was inserted was placed on the gas outlet 13 at the center of the chamber of the generated gas collector (MSTD-258M manufactured by GL Sciences Co., Ltd.) with the support side of the sample 9 facing downward (gas outlet). 13) Then, clean helium gas 11 was supplied at a flow rate of 240 ml / min.
The inside of the chamber 10 is heated at 60 ° C. while continuously flowing through the column, and after 30 minutes, the solid adsorbent 13 (component: 2,6-diphenylene oxiside) is added to the solid adsorbent 13 at a collection rate of 100 ml / min.
Time collected. For the other sample 9, the generated gas was collected by the same procedure with the heating rate of the chamber 10 set to 80 ° C. Estimated gas generated at 23 ° C by the generated gas estimation method, and the amount of gas generated per unit area of the unit when the filter medium for chemical filter was molded into a pleated type unit (3.3 cm in height, 5 mm in mountain) Table 1
Summarized in

【table 1】

As shown in Table 1, the filter media for chemical filters of Examples 1 and 2, in which a physical adsorption layer was provided downstream of the ion-exchange resin layer in the passage direction of the gas to be treated without using a cover material, The amount of organic substances generated per unit frontage area of the unit is small, and the amount of additives is below the quantification limit (1.0 pg / m ²
-Hr or less). In Example 3 in which the cover material was used, the total amount of organic substances generated in the cover material was small, and the total amount of organic substances generated and the amount of additives were small as a filter material for a chemical filter.

(Method for Evaluating Physical Properties of Gas Removal of Filter Material for Chemical Filter) A method for evaluating physical properties of gas removal for a filter material for chemical filter uses ammonia as a pollutant gas and an initial concentration of 25%.
ppm, wind speed 3.5 cm / sec, temperature 23 ° C, relative humidity 4
Performed under the condition of 5% RH. The difference between the initial concentration (upstream concentration) and the downstream concentration after passing through the filter medium for a chemical filter was divided by the initial concentration and determined as a percentage, which was defined as the contaminant gas removal efficiency. Thereafter, the upstream concentration and the downstream concentration were measured over time, and it was determined that the life was reached when the removal efficiency was reduced to 90%.
Breakthrough time. The results are shown in Table 2.

[Table 2] * Initial removal rate: Pollution gas removal rate 1 minute after starting to pass the pollutant gas through the chemical filter

As shown in Table 2, Example 1 or Example 3 had a longer breakthrough time than Comparative Example 1 in which no physical adsorption layer was used. In addition, Example 2 using impregnated activated carbon had a breakthrough time longer by about 20% than Example 1, Example 3, or Comparative Example 1 using no impregnated carbon.

[0041]

The filter material for a chemical filter and the chemical filter unit of the present invention, when used in a clean room or the like, can remove particularly acidic or basic gas, and furthermore, the filter material for a chemical filter and the chemical filter unit themselves can remove gas from the chemical filter unit. No gaseous pollutants are generated, or the amount of gaseous pollutants generated is extremely small, and does not adversely affect products in the clean room.

[Brief description of the drawings]

FIG. 1 is a sketch of a pleated chemical filter unit of the present invention.

FIG. 2 is a sketch of a panel-type chemical filter unit of the present invention.

FIG. 3 is a schematic cross-sectional view of a filter material for a chemical filter of the present invention.

FIG. 4 is a schematic sectional view of a filter material for a chemical filter having a cover material of the present invention.

FIG. 5 is an explanatory diagram of a generated gas collecting device used for a dynamic headspace method.

[Explanation of symbols]

 REFERENCE SIGNS LIST 1 unit frame 2 support 3 cover material 4 direction of passage of specific processing gas 5 connecting portion 5a adhesive layer 6 resin aggregation portion 6a resin aggregation portion 7a ion exchange resin 7b ion exchange resin or physical adsorbent 7c physical adsorbent 8a ion exchange Resin layer 8b Ion exchange resin layer or physical adsorption layer 8c Physical adsorption layer 9 Sample 10 Chamber 11 Helium gas 12 Solid adsorbent 13 Gas outlet

Claims (6)

[Claims] 1. A filter material for a chemical filter, wherein a physical adsorption layer for adsorbing contaminants generated from the ion exchange resin layer is laminated downstream of the ion exchange resin layer. 2. The method according to claim 1, wherein the ion-exchange resin layers, the physical adsorption layers, or the ion-exchange resin layer and the physical adsorption layer are bonded and integrated by a heat-fusible resin. 2. The filter material for a chemical filter according to 1. 3. The filter medium for a chemical filter according to claim 1, wherein the physical adsorption layer includes an acidic gas adsorbent and / or an alkali gas adsorbent. 4. A web composed of a plurality of lamination units, the lamination unit comprising a connecting portion made of a hot melt resin and a resin aggregation portion, on one surface of a web via the resin aggregation portion. The other surface of the web and the ion-exchange resin particles or the physisorptive particles constituting another lamination unit are formed by adhering the particles or the physically adsorbed particles via a resin aggregation portion. The filter medium for a chemical filter according to any one of claims 1 to 3, wherein the filter unit is formed by adhering, and the lamination unit is the ion exchange resin layer or the physical adsorption layer. 5. The chemical filter unit comprising a filter material for a chemical filter according to claim 1, wherein a cover material is provided further downstream of the layer laminated at the most downstream position. When the mass (toluene-equivalent weight) was calculated at 23 ° C. by the evolved gas estimation method, the total organic substance amount was 1.0 (pg / m 2) per unit area of the chemical filter unit and per unit time.
^A chemical filter unit having a value of not less than ² · hr) and not more than 10 (μg / m ² · hr). 6. The chemical filter unit comprising the filter material for a chemical filter according to claim 1, further comprising a cover material provided further downstream of the layer laminated at the most downstream position, wherein an additive generated from the cover material is provided. When the amount (weight in terms of toluene) was calculated at 23 ° C. by the generated gas estimation method, the amount of the additive was 1.0 (pg / m ² ·· m) per unit area of the chemical filter unit and per unit time.
hr) to 0.15 (μg / m ² · hr) or less.